android - Can anyone explain me this code? -

import org.apache.http.message.basicnamevaluepair;  private string getserverdata(string returnstring) {                inputstream = null;  string result = ""; //the year data send arraylist<namevaluepair> namevaluepairs = new arraylist<namevaluepair>(); namevaluepairs.add(new basicnamevaluepair("year","1970"));  //http post try{        httpclient httpclient = new defaulthttpclient();        httppost httppost = new httppost(key_121);        httppost.setentity(new urlencodedformentity(namevaluepairs));        httpresponse response = httpclient.execute(httppost);        httpentity entity = response.getentity();        = entity.getcontent();  }catch(exception e){        log.e("log_tag", "error in http connection "+e.tostring()); } } 

my questions...

what basicnamevaluepair class does?

what piece of line

httppost.setentity(new urlencodedformentity(namevaluepairs)); 

what is = entity.getcontent(); do? , can pass more 1 value in basicnamevaluepair class. can entirely pass vo instead of this.

like below ...

namevaluepairs.add(new basicnamevaluepair("year","1970","sas","saassa","sas","asas")); 

basicnamevaluepair object, container holds data , keys.

for example if have data:

name: bob  family name: smith  date of birth: 10/03/1977 

then store data as:

arraylist<namevaluepair> namevaluepairs = new arraylist<namevaluepair>();  namevaluepairs.add(new basicnamevaluepair("name","bob"));  namevaluepairs.add(new basicnamevaluepair("family name","smith"));  .... 

as see choose key ("name") , data stored linked key ("bob"). it's type of data structure used speed , make easier store kind of informations.

on other end need tool use data:

httppost.setentity(new urlencodedformentity(namevaluepairs)); 

this code can divided in 4 parts:

httppost.setentity 

is method take url argument, , tries retrieve data (html or stored on page) url, using http post method.

new urlencodedformentity

is method trasform key-data value pair in intelligible http server.

it use convention

&key=input 

which 1 of used, remember there more ways it.

namevaluepair 

is data stored before. in case has key possible input forms in html, identified "input name=" tag. data has value want give forms.

is = entity.getcontent(); 

httpentity abstraction handle possible result. if web site unreachable or connection down, httpentity inform you. getcontent() method use retrieve body of http result, i.e.: html webserver sent back, inputstream. if request wasn't succesfull give null value.

basicnamevaluepair accept couplets, you'll have cast multiple times , everytime add arraylist.

you can't cast more 2 values, meaningless (key, value) representation of data.

hope helped.